Hey there!
I am a KDE user and pretty much cannot switch. I dont have issues with the desktop really, it has some unique and powerful apps, and the desktop pretty much just works for me.
I tried GNOME and COSMIC, and pretty much the whole problem is, that KDE apps don’t force their theme like GTK3-4/Libadwaita apps do.
KDE apps are totally broken, even though they shouldn’t?
Has this changed, and if not, can you somehow force the icons and theme for KDE/Qt/Breeze apps?
I will experiment and add screenshots